Who’s Who in Climate

by Bill Chameides | July 15th, 2010
posted by Erica Rowell (Editor)

Permalink | 12 comments

Do you have to be an expert to know which way the climate goes?

I am constantly being asked: Is there really a scientific consensus on climate change? Answering objectively is difficult. How do you define a consensus?

Nevertheless, it seems to me there is consensus: Climate change is real, largely caused by humans, and poses serious problems for society. My judgment is based on lots of stuff, not the least of which are statements to that effect from leading scientific organizations such as the U.S. National Academy of Sciences, which was established by Congress in 1863 to advise the nation on scientific and technical issues … such as those surrounding climate change and how to solve it.

But others put less stock in the wisdom and judgment of the National Academy of Sciences, pointing instead to other statements endorsed by hundreds and even thousands of scientists rejecting the notion that the globe is warming and/or that it’s due to human activities or is of any consequence. How, the climate skeptics ask, can there possibly be a consensus when so many scientists say there is not?

How to Resolve a Dispute Between ‘Experts’? Rank Them

One answer often heard is that the scientists signing on to those contrarian statements are not really climate experts, and so their dissenting opinions don’t really count. (Here’s an example.)

To put substance behind that argument, a group of scientists from Stanford University, led by William R. L. Anderegg, assessed the “climate expertise and scientific prominence” of two groups of climate researchers whose names are attached to the most prominent climate change statements: those who subscribe to the tenets of anthropogenic climate change and those who do not. The authors published their results last week in the Proceedings of the National Academy of Sciences.

Substantial Differences Were Found Between the Two Groups of Climate Scientists

From a beginning database of 1,372 climate scientists, the authors focused on 908 researchers who had at least 20 publications as a minimum measure of expertise.

Those meeting this minimum expertise criterion included:

  • more than 90 percent of those who accept human-caused climate change, and
  • about 20 percent of climate scientists who do accept anthropogenic climate change.

An even greater disparity was found when “the 50 most-published (highest-expertise) researchers from each group” were compared:

  • the top-published researchers accepting manmade global warming had an average of 408 climate publications;
  • the top-published scientists in the non-accepting camp had an average of 89 publications.

To measure the scientific weightiness of the work, the authors also evaluated the number of times publications were cited by others. Again, a significant disparity:

  • the top four papers authored by scientists who subscribe to global warming were cited an average of 133 times;
  • the top four papers authored by scientists who do not subscribe to global warming were cited on average 84 times.

The authors concluded:

“We show that the expertise and prominence, two integral components of overall expert credibility, of climate researchers convinced by the evidence of ACC [anthropogenic climate change] vastly overshadows that of the climate change skeptics and contrarians. … Despite media tendencies to present both sides in the ACC debate … not all climate researchers are equal in scientific credibility and expertise in the climate system. This extensive analysis of the mainstream versus skeptical/contrarian researchers suggests a strong role for considering expert credibility in the relative weight of and attention to these groups of researchers in future discussions in media, policy, and public forums regarding anthropogenic climate change.”

In other words:

  • There really is consensus among the really good climate scientists.
  • The consensus is that climate change is caused by humans and is a serious problem.

The Contrarian Response

Not surprisingly there’s been a quick response to the study in the contrarian blogosphere (see here and here). The primary argument is that the study merely confirms what they’ve been complaining about for years: namely that the climate science community has become a cabal wedded to a flawed scientific analysis (and for some, a sinister political agenda) that has effectively “black-listed” contrarian scientists from publications and grants. The lack of impressive statistics for contrarian scientists is not from a lack of expertise, they argue, but from a lockout.

I don’t buy it. In my experience (which includes an editor position at a major scientific journal), while mistakes are sometimes made in the peer-review process, the contents of peer-reviewed literature are largely determined by quality not the pre-conceived notions of reviewers or editors. Reviewers cannot recommend rejecting a paper simply because they don’t “like” or “agree” with it. Such recommendations must be based on the identification of flawed data, analysis or methods. Frequently reviewers recommend publication of papers whose conclusions they do not subscribe to.

My Reservations About the Study

But I do have some reservations about the paper. For one, I am concerned about the terminology the authors chose to describe the two scientific groups: “convinced by the evidence” for adherents to anthropogenic climate change and in my opinion the somewhat pejorative “unconvinced by the evidence” for the non-adherents to anthropogenic climate change, seemingly denying the possibility that any “evidence” could support the dissenting viewpoint.

I’m also somewhat uncomfortable with the paper’s ad hominem tenor — a seeming attack on the messengers of contrariness rather than on the substance of their arguments.

Still, Dismissing the Paper Would Be a Mistake

But I also know that it is common practice to check someone’s credentials before buying his or her services. In our highly technical world, we as a society must turn to experts on a wide range of issues, and when do, we want to make sure those people really are expert. To do this, we need standards and metrics. And in the science world the metrics include publications and citations.

And at least when it comes to these metrics, Anderegg et al. show fairly convincingly those in the contrarian camp don’t measure up nearly as well as those who support the tenets of anthropogenic climate change. You can choose to ignore that distinction, but before you do, consider this: If you needed an operation, which surgeon would you choose? One with a long and distinguished track record who is ranked in the top tier of doctors or one without such distinctions?

As in many things, when it comes to the climate science marketplace, it’s caveat emptor.

filed under: climate change, faculty, global warming, science
and: , , ,


All comments are moderated and limited to 275 words. Your e-mail address is never displayed. Read our Comment Guidelines for more details.

  1. MattN
    Aug 6, 2010 “The paper is poorly done, as I’ve explained elsewhere. They used Google Scholar instead of an academic database. They searched only in English, despite the global nature of climate science. They got names wrong. They got job titles wrong. They got incorrect numbers of publications and citations. As I’ve mentioned, the highly respected Spencer Weart dismissed the paper as rubbish, saying it should not have been published. …. The paper is tagged ‘Climate Deniers.’ Now, so are they. This is an outright violation of every ethical code of conduct for research that has ever been published.” Agreed 100%….

  2. MattN
    Jul 25, 2010

    Why didn’t you publish my 1st comment Doc? A little too truthy? The creation of a blacklist has no place in science. Anderegg should just go ahead and change his name to McCarthy. “Are you now or have you ever been a climate change denier…?” Just awesome. I weep for the state of science…

    • Erica Rowell (Editor)
      Jul 26, 2010

      MattN, I sometimes hold off on posting comments of yours that border on being uncivil like the one you refer to here, which I did indeed eventually publish. But note that uncivil comments will not be published. Please watch your tone and civility and help to create a good discussion space where informed ideas are welcome and propagated — and where civil posts, no matter dissenting or agreeing, are published. Thank you, Erica Rowell Editor, TheGreenGrok

      • MattN
        Jul 26, 2010

        That brings me to another fine point. You just LOVE to not publish my last comment until after the comments close (30 days after initial posting) then publish your own witty retort at the same time thereby having the “last word” so I can’t respond. (see: my last comment in US Temp record entry dated July 26th). Go ahead. Tell me I’m wrong…

        • Erica Rowell (Editor)
          Aug 3, 2010

          MattN, There is no conspiracy theory here on the blog with regard to the timing of posting comments. If I wait to post a comment (rather than reject it immediately), the reason is simply, as I explained above, that I’m on the fence about it — I find it borderline publishable. (Sometimes I run those by Bill to get his take on whether he thinks they’re appropriate or not, and that adds time.) I do not keep calendrical track of pending comments. The simple way around a wait is to be civil in all posts. That makes my moderating job easier and eliminates excessive wait times. Cheers, Erica

  3. MattN
    Jul 16, 2010

    …Is absurd, even for you Doc. You should have stayed on vacation longer…

  4. Ken Towe
    Jul 23, 2010

    My comment on a graduate student as an “expert” was intended to be a joke. Obviously, it didn’t go over well. You are quite correct that it is no reason to dismiss the paper, especially as he had several experienced co-authors. My experiences with controversial topics as an editor (and as author and co-author) must have been different from yours. Few referees were happy to agree with those whose views differed from theirs. However, almost any paper that was in agreement got a pass. The resistance to cite opposing views, recommend publication of opposing views, invite opposing views to speak at meetings was commonplace. Which of the places at Green Grok cited in your GrokRoll list is the most objective representation of the contrarian views of climate for others to read and evaluate?

    • Bill Chameides
      Aug 3, 2010

      Ken: 1. Happiness has little to do with reviewing papers. I can recall many, many instances where reviewers did not agree with conclusions and, while they may have insisted on adding caveats, gave the paper a “pass.” If anything, the literature is tainted by too many low-quality papers, not by an absence of papers that were deserving of publication. 2. The Grok Roll is a far cry from a peer-reviewed journal, or was that a joke as well.

  5. Ken Towe
    Jul 19, 2010

    Checking credentials? The lead author, WRL Anderegg, appears to be a “convinced” graduate student in biology with only an abstract to his publication credit. His abstract had “climate change” in the title so I guess that makes him a climate scientist. As a former editor-in-chief and associate editor for three different scientific publications, I know that it is not just the identification of flawed data, methods etc. that dooms a paper. When referees meet a paper (or author) they don’t like, but in which they cannot find serious flaws, it is the subtle damn-with-faint-praise approach that is tried [usually in a covering letter to the editor]. Examples: “This is a fascinating paper but they would be better off to publish elsewhere.” or: “…a most interesting paper but the conclusions would be stronger if it had more data.”or… “although one hates to disqualify a paper simply because one disagrees with the author’s point of view, it needs more work before revision.” In my editorial experience, it is much less frequent that “peers” recommend publication of papers whose conclusions they do not support. It is certainly not a frequent occurrence. It is also much less frequent that dissenting papers are even mentioned in establishment papers (they don’t want the unwary reader to even know about them). Contrarians, on the other hand, usually cite some ‘dogma’ as introductory material. Establishment authors love to cite papers of those who agree with them, tending to cite one another and themselves. After all, self-citations add to their citation index scores. These are common problems and are bound to skew the citation results as to who and where the ‘experts’ are.

    • Bill Chameides
      Jul 23, 2010

      Ken: You miss the point in your undercutting of the, admittedly very thin, credentials of Anderegg. The point of the paper was not on whether someone with few credentials in the climate field can publish a worthy, credible paper on climate or any other topic. Of course he or she can, and in fact it is not all that uncommon for a graduate student to publish a seminal paper. The question has to do with expertise: who you would turn to for an expert opinion on a topic such as the robustness of the science behind anthropogenic climate change. Clearly someone like Anderegg would not be someone who would be considered an expert and whose opinions on the subject would carry much weight. The point of the paper was to objectively rate the relative expertise and credentials of the various people involved in the climate debate. There is no reason to discount the paper because Anderegg is not an “expert.” Your comments about the peer-review process are well taken; I just don’t happen to agree — a clash of experts I suppose. It is possible that you and I were quite different editors.

©2015 Nicholas School of the Environment at Duke University | Box 90328 | Durham, NC 27708
how to contact us > | login to the site > | site disclaimers >

footer nav stuff